1. Field of the Invention
The present invention relates to a pipe coupling, and more specifically relates to a pipe coupling that has a small number of parts, is easy to assemble and is provided with simplified flow adjustment and residual pressure removal functions.
FIG. 15 is a longitudinal cross section of a female coupling member of a conventional type of this pipe coupling, where FIG. 16 is a side view of this coupling member.
2. Description of the Background Art
This female coupling member is provided with a coupling body 110 that has a fluid passage 114, such that it is inserted into and connected to a male coupling member (not shown) at the right side when seen in the drawing.
The coupling body 110 has a valve mechanism 111 provided with a valve 113 that opens or closes the fluid passage 114, a connecting mechanism 116 that maintains the state of connection to the male coupling member, and a fluid pressure purging mechanism 118 provided with a purge passage 119 for purging the fluid pressure within the fluid passage 114 in the interior of the male coupling member.
The valve 113 is spherical overall, being supported by valve seats 113a, 113a. When this valve is in the position shown in the drawing, the valve hole 113b provided thereon is turned away from the fluid passage 114, so the valve is closed. When the valve is rotated by 90° from the position shown in the drawing, the valve hole is aligned to the fluid passage 114 so the valve is open. Thus, it is possible to adjust the flow of the fluid flowing through the fluid passage by adjusting the rotary position of the valve.
The connecting mechanism 116 has a locking member (locking ball) 115 and a sleeve 117. The locking member engages an engaging groove on the outside surface of the male coupling member inserted into the interior of the male coupling member, thus securing (locking) the male coupling member to the female coupling member. The sleeve 117 is able to move between a position that permits the locking member 115 to assume a position on the outside in the radial direction (unlocked position) shown in the drawing, and a position that holds the locking member from the outside in the radial direction, when the male coupling member is inserted into the interior of the female coupling member while pushing in the locking member support member 120, and when the locking member 115 engages the engaging groove of the male coupling member and moves to the inside position in the radial direction (locked position), thus moving toward the right side from the illustrated position.
The purge mechanism has a sleeve 121b that contacts the sleeve 117 of the connecting mechanism. A pair of sealing rings 121a provided on the inside surface of the sleeve 121b are positioned on either side of the outlet of the purge passage 119 on the outside in the radial direction, and are able to move between a position that blocks the fluid pressure within the fluid passage 114 from being released into the outside, and a position to the left of this position, which is a position that permits the fluid pressure within the fluid passage 114 to pass through a gap S between the sleeve 117 and coupling body 110 and be released outside.
The valve mechanism 111 is provided with a cam 112 that rotates together with the valve, and this cam controls the connecting mechanism 116, sealing ring support 118 and this valve mechanism. When the valve 113 is in the closed state as illustrated in the drawing, the connecting mechanism 116 is such that the locking member 115 is in the outside position in the radial direction (locked position), thus permitting the male coupling member to be inserted into or withdrawn from the female coupling member, and also the purge mechanism 118 allowing the fluid pressure from the fluid passage 114 to be released into the outside. In this state, the sleeve 117 engages the locking member 115, so the valve cannot be rotated (namely, the cam cannot move the sleeve 121b and sleeve 117 to the right). If the male coupling member is inserted in this state, the locking member 115 can be moved to the inside position in the radial direction (unlocked position), and if the valve 113 is rotated .to the open state, the cam 112 pushes the sleeve 121b and sleeve 117 so that the purge passage 119 of the purge mechanism 118 is blocked by the sealing rings 112a, 112a, and at the same time, the sleeve 117 secures the locking member 115 in the locked position. Conversely, when the valve 113 is returned to the closed state, the sleeve 121b is moved to the left by a spring 124 located between it and the sleeve 117 and returned to the position of FIG. 15, so the fluid pressure within the fluid passage can be released through the purge mechanism 118 and the connection to the male coupling member can be released.
These mechanisms are intended to maintain safety during the connection and disconnection of the male coupling members, but their structure is complex and they have various accompanying problems.
There are couplings that have similar structures used on supply lines for high-pressure fluids, but in this case, valves are provided on both the fluid intake-side end and fluid discharge-side end (male coupling member connection side) of the fluid passage of the male coupling member, but the structure becomes even more complex (see Japanese Patent No. 2694302, for example).